SU765954A1 - Self-oscilator - Google Patents

Description

(54) AUTOGENERATOR

one

The invention relates to converter equipment and can be used in automation and secondary power devices.

Circuits of transistor generators with saturating power transformer 1 are known.

The disadvantage of this device is that the switching moment of the transistors is determined by the output from the saturation state of the previously open transistor. At the same time, the collector current increases to a value equal to the product of the base current and the static gain of the transistor. Since the current pulse amplitude cannot exceed the maximum permissible value for the transistor, the rated collector current can not be greater than the product of the permissible pulse collector current by the ratio of the minimum to maximum static transistor gain factors, which sometimes causes significant underuse of transistors by the average collector current, or forces you to pick up transistors with close gains.

The closest to the proposed technical entity is an inverter that contains a current sensor with a transistor and a key controlled by the latter, connected via diodes with power transistors, between the emitters of which and the input terminal, a third power zener diode.

The disadvantage of the device is reduced efficiency due to the presence in the power supply circuit of an additional transistor.

10 The purpose of the invention is to simplify and increase the efficiency.

The goal is achieved by switching on a current sensor between the input terminal and the midpoint of the collector windings of the transformer and the emitter connection

5 power transistors with a different input terminal. In addition, the controlled key is made in the form of two transistors, the power transitions of which shunt the control transitions of the power transistors.

2Q FIG. 1 is a schematic diagram of an auto generator; in fig. 2 - timing diagram of the collector current.

The auto-generator consists of power transistors 1 and 2. connected to an output transformer 3, the power supply of which includes a current sensor 4, shunted by a control junction of transistor 5, the collector of which is connected through resistors 6 and 7 to the input of a control key made on transistors 8 and 9.

The scheme works as follows.

When the magnetic core of the transformer 3 is saturated, the magnetizing current of the latter, and hence the collector current of the open transistor, for example 2, starts to increase. When the voltage across the measuring resistor 4 reaches the value of unlocking the emitter junction of transistor 5, the latter opens, filling its collector tokbm transistors 8 and 9, which, in turn, bypass the emitter junction of the main transistors 1 and 2, forced the closing of the open transistor 2. Consequently , maximum collector current of power transistors in. switching time does not depend on the gain of the latter, but is determined by the value of resistor 4.

Timing diagrams of the currents consumed by the oscillator are shown in FIG. 2 a, b for schemes 1 and proposed, respectively. The ratio of the values of IcMW-ctnAx and corresponds to the passport data of the most common types of key transistors 2T630, 2T603, 2T208.

Thus, one power transistor with a zener diode shunting it and a source feeding the base circuit of the specified transistor (two diodes) are excluded from the known circuit, which improves the efficiency and simplifies the circuit while maintaining the positive qualities of the known device.

Claims (2)

1.Auto generator containing power transistors connected to an output transformer, the sensor circuit connected by a control transition of the transistor, whose collector is connected to the input of a control key connected to the control transitions of power transistors, characterized in that in order to simplify and increase the efficiency, the current sensor is connected between the input terminal and the midpoint of the collector windings of the transformer, and the emitters of the power transistors are connected to another input terminal. 2. The autogenerator according to claim 1, characterized in that the control key is made in the form of two transistors, the power transitions of which bypass the control transitions of the power transistors. Sources of information taken into account in the examination. Moin V.S. and Laptev N.N. Stabilized transistor converters. M., “Energie, 1972, p. 311, fig. 9-5 a, b, g, d. 2. US patent No. 3956684, cl. H 02 M 7/5 5, 1976. four 0 t-HIID FIG.  -f DS / "G / 7 OL -experience ABOUT) l L7y / 7 b) FIG. 2